Variable stiffness prosthetic foot

ABSTRACT

Prosthetic feet that provide for variable and adjustable stiffness are provided. A foot element can include a tongue portion defined or formed by a slot in the foot element that at least partially separates the tongue portion from a remainder of the foot element. The tongue portion can be operably connected to the remainder of the foot member to increase the stiffness of the foot member or operably disconnected from the remainder of the foot member to increase the flexibility of the foot member. The prosthetic foot further includes a mechanism for adjusting whether the tongue portion is operably connected or disconnected from the remainder of the foot member. The mechanism can be selectively actuated to adjust the stiffness of the foot element in dorsiflexion and/or plantarflexion and/or to adjust the degree to which the tongue portion is allowed to flex relative to the remainder of the foot member.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57. Thisapplication is a divisional application of U.S. patent application Ser.No. 14/858,693, filed on Sep. 18, 2015, entitled “VARIABLE STIFFNESSPROSTHETIC FOOT”, now U.S. Pat. No. 10,034,782, which claims thepriority benefit of U.S. Provisional Application No. 62/053,000, filedSep. 19, 2014, the entirety of which is hereby incorporated by referenceherein and should be considered part of this specification.

BACKGROUND Field

The present disclosure relates generally to prosthetic feet. In someembodiments, the present disclosure relates more specifically toprosthetic feet having adjustable stiffness and flexibilitycharacteristics.

Description of the Related Art

Various types of prosthetic feet are available as substitutes fornatural human feet. Such feet can be made of various materials havingvarious stiffness or flexibility characteristics. Existing feetgenerally have a predetermined stiffness level as defined by, forexample, the material(s) making up the foot, thickness of the footplate, etc.

SUMMARY

Some aspects of the present disclosure provide for prosthetic feethaving adjustable stiffness characteristics.

In some embodiments, a prosthetic foot includes an elongate foot elementextending from a proximal end to a toe end. The foot element includes atongue portion defined by a generally U-shaped cutout in the footelement. The tongue portion is configured to flex at least partiallyindependently of a remainder of the foot element. The prosthetic footfurther includes a mechanism configured to be selectively actuated tooperatively connect or operatively disconnect the tongue portion fromthe remainder of the foot element. When the tongue portion isoperatively connected to the remainder of the foot element, the footelement exhibits relatively greater stiffness, and when the tongueportion is operatively disconnected from the remainder of the footelement, the foot element exhibits relatively lower stiffness.

The mechanism can be configured to be selectively actuated to adjust thestiffness of the foot element in one or both of plantarflexion anddorsiflexion. In some embodiments, the mechanism includes first andsecond engagement members coupled to the tongue portion. The firstengagement member is disposed on a front side of the foot element andthe second engagement member is disposed on a back side of the footelement. The first engagement member is configured to be actuated toselectively operatively connect or operatively disconnect the tongueportion from the remainder of the foot element in dorsiflexion, and thesecond engagement member is configured to be actuated to selectivelyoperatively connect or operatively disconnect the tongue portion fromthe remainder of the foot element in plantarflexion.

In some embodiments, the mechanism includes a shaft extending through anaperture near a proximal end of the tongue portion, a flange at a firstend of the shaft, an adjustment knob at a second end of the shaft, awasher slidably disposed on the shaft between the adjustment knob andthe foot element, and a spring disposed around the shaft. The springextends between and is coupled to the adjustment knob and the washer.The tongue portion is disposed between the flange and the washer, andthe knob is selectively adjustable to vary a stiffness of the footelement. In some embodiments, the mechanism further includes a secondwasher and a second spring. The second spring is interposed about theshaft between the second washer and the flange, and the tongue portionis interposed between the washer and the second washer.

In some embodiments, the mechanism includes a shaft extending through anaperture near a proximal end of the tongue portion, a first adjustmentknob at a first end of the shaft, a first washer slidably disposed onthe shaft between the first adjustment knob and a rear side of the footelement, a spring disposed around the shaft and extending between andcoupled to the first adjustment knob and the first washer, a secondadjustment knob at a second end of the shaft, a second washer slidablydisposed on the shaft between the second adjustment knob and a frontside of the foot element, and a second spring disposed around the shaftand extending between and coupled to the second adjustment knob and thesecond washer. The first and second knobs are selectively adjustable torespectively and independently vary a stiffness of the foot element inplantarflexion and dorsiflexion.

In some embodiments, a prosthetic foot includes an elongate foot elementextending from a proximal end to a toe end. The foot element includes atongue portion defined by a generally U-shaped cutout in the footelement. The tongue portion is configured to flex at least partiallyindependently of a remainder of the foot element. The prosthetic footfurther includes means coupled to the tongue portion for selectivelyadjusting a stiffness of the elongate foot element during one or both ofthe dorsiflexion and plantarflexion between at least two differentstiffness levels.

In some embodiments, the means is configured to independently vary astiffness of the foot element in dorsiflexion and plantarflexion. Insome embodiments, the means selectively operatively connects the tongueportion to or from the remainder of the foot element to thereby adjustthe stiffness of the elongate foot element during one or both ofdorsiflexion and plantarflexion. When the tongue portion is operativelyconnected to the remainder of the foot element, the foot elementexhibits relatively greater stiffness, and when the tongue portion isoperatively disconnected from the remainder of the foot element, thefoot element exhibits relatively lower stiffness.

According to one aspect of the present disclosure, there is provided aprosthetic foot that includes an elongate foot element extending from aproximal end to a distal end, the foot element comprising a tongueportion defined by a slot in the foot element that at least partiallyseparates the tongue portion from a remainder of the elongate footelement. The prosthetic foot further includes a mechanism configured tobe selectively actuated to operatively connect or operatively disconnectthe tongue portion from the remainder of the foot element, wherein whenthe tongue portion is operatively connected to the remainder of the footelement the foot element exhibits relatively greater stiffness, and whenthe tongue portion is operatively disconnected from the remainder of thefoot element the foot element exhibits relatively lower stiffness.

The prosthetic foot may be arranged such that the mechanism isconfigured to be selectively actuated to adjust the stiffness of thefoot element in one or both of plantarflexion and dorsiflexion. Theprosthetic foot may be arranged such that the mechanism furthercomprises first and second engagement members coupled to the tongueportion, the first engagement member disposed on a front side of thefoot element and the second engagement member disposed on a back side ofthe foot element, wherein the first engagement member is configured tobe actuated to selectively operatively connect or operatively disconnectthe tongue portion from the remainder of the foot element indorsiflexion, and wherein the second engagement member is configured tobe actuated to selectively operatively connect or operatively disconnectthe tongue portion from the remainder of the foot element inplantarflexion.

The prosthetic foot may be arranged such that the mechanism comprises ashaft extending through an aperture near a proximal end of the tongueportion, a flange at a first end of the shaft, an adjustment knob at asecond end of the shaft, a washer slidably disposed on the shaft betweenthe adjustment knob and the foot element, and a spring disposed aroundthe shaft and extending between and coupled to the adjustment knob andthe washer, wherein the tongue portion is disposed between the flangeand the washer and wherein the knob is selectively adjustable to vary acompression of the spring to adjust a stiffness of the foot element. Theprosthetic foot may be arranged such that the mechanism furthercomprises a second washer and a second spring, the second springinterposed about the shaft between the second washer and the flange, andwherein the tongue portion is interposed between the washer and thesecond washer.

The prosthetic foot may be arranged such that the mechanism comprises ashaft extending through an aperture near a proximal end of the tongueportion, a first adjustment knob at a first end of the shaft, a firstwasher slidably disposed on the shaft between the first adjustment knoband a rear side of the foot element, and a spring disposed around theshaft and extending between and coupled to the first adjustment knob andthe first washer, a second adjustment knob at a second end of the shaft,a second washer slidably disposed on the shaft between the secondadjustment knob and a front side of the foot element, and a secondspring disposed around the shaft and extending between and coupled tothe second adjustment knob and the second washer, wherein the tongueportion is disposed between the first and second washers, and whereinthe first and second knobs are selectively adjustable to respectivelyand independently vary a stiffness of the foot element in plantarflexionand dorsiflexion.

The prosthetic foot may be arranged such that when the tongue portion isoperatively connected to the remainder of the foot element the tongueportion flexes with the remainder of the foot element, and when thetongue portion is operatively disconnected from the remainder of thefoot element the tongue portion flexes at least partially independentlyof the remainder of the foot element. The prosthetic foot may further bearranged such that the tongue portion is configured to flex with theremainder of the foot element during one of plantarflexion anddorsiflexion and configured to flex at least partially independently ofthe remainder of the foot element during the other of plantarflexion anddorsiflexion.

The prosthetic foot may further include an adapter coupled to the footelement proximate to the proximal end.

The prosthetic foot may be arranged such that the distal end of the footelement defines a toe portion.

The prosthetic foot may further include a second foot element disposedbelow the foot element. The prosthetic foot may further be arranged suchthat the second foot element extends from a heel end to a toe end of theprosthetic foot. Alternatively, the prosthetic foot may be arranged suchthat the second foot element is a heel plate that extends from a heelend of the prosthetic foot to a location proximal of the distal end ofthe foot element.

According to another aspect of the present disclosure, a prosthetic footis provided that includes an elongate foot element extending from aproximal end to a distal end, the foot element comprising a tongueportion defined by a slot in the foot element that at least partiallyseparates the tongue portion from a remainder of the elongate footelement. The prosthetic foot also includes means for selectivelycoupling the tongue portion with the remainder of the foot element forselectively adjusting a stiffness of the elongate foot element duringone or both of dorsiflexion and plantarflexion between at least twodifferent stiffness levels.

The prosthetic foot may be arranged such that the means is configured toindependently vary a stiffness of the foot element in dorsiflexion andplantarflexion.

The prosthetic foot may be arranged such that the means selectivelyoperatively connects or operatively disconnects the tongue portion fromthe remainder of the foot element to thereby adjust the stiffness of theelongate foot element during one or both of dorsiflexion andplantarflexion, wherein when the tongue portion is operatively connectedto the remainder of the foot element, the foot element exhibitsrelatively greater stiffness, and when the tongue portion is operativelydisconnected from the remainder of the foot element, the foot elementexhibits relatively lower stiffness.

The prosthetic foot may be arranged such that when the tongue portion iscoupled to the remainder of the foot element the tongue portion flexeswith the remainder of the foot element, and when the tongue portion isnot coupled to the remainder of the foot element the tongue portionflexes at least partially independently of the remainder of the footelement. The prosthetic foot may further be arranged such that thetongue portion is configured to flex with the remainder of the footelement during one of plantarflexion and dorsiflexion and configured toflex at least partially independently of the remainder of the footelement during the other of plantarflexion and dorsiflexion.

According to another aspect of the present disclosure, a prosthetic footis provided that includes a first elongate foot element and a secondfoot element. The first elongate foot element extends from a proximalend to a distal end and comprises a tongue portion defined by a slot inthe foot element that at least partially separates the tongue portionfrom a remainder of the first elongate foot element. The second footelement is disposed below and coupled to the first elongate footelement, and the distal end of the first elongate foot element ispositioned proximal of the toe end of the second foot element. Theprosthetic foot also includes a mechanism configured to be selectivelyactuated to operatively connect or operatively disconnect the tongueportion from the remainder of the first elongate foot element, whereinwhen the tongue portion is operatively connected to the remainder of thefirst elongate foot element the first elongate foot element exhibitsrelatively greater stiffness, and when the tongue portion is operativelydisconnected from the remainder of the first elongate foot element thefoot element exhibits relatively lower stiffness.

The prosthetic foot can be arranged such that the first elongate footelement is generally C-shaped.

The prosthetic foot can be arranged such that the mechanism comprises atleast one tab engagement member and wherein the tongue portion isoperatively connected to the remainder of the first elongate footelement when the tab engagement member is positioned in a firstorientation and the tongue portion is operatively disconnected from theremainder of the first elongate foot element when the tab engagementmember is positioned in a second orientation. The prosthetic foot mayfurther be arranged such that the at least one tab engagement membercomprises two tab engagement members, a first tab engagement memberdisposed on a front side of the first elongate foot element and a secondtab engagement member disposed on a back side of the first elongate footelement.

The prosthetic foot can be arranged such that the tongue portion isoperatively connected to the remainder of the first elongate footelement the tongue portion flexes with the remainder of the firstelongate foot element, and when the tongue portion is operativelydisconnected from the remainder of the first elongate foot element thetongue portion flexes at least partially independently of the remainderof the first elongate foot element. The prosthetic foot may further bearranged such that the tongue portion is configured to flex with theremainder of the first elongate foot element during one ofplantarflexion and dorsiflexion and configured to flex at leastpartially independently of the remainder of the first elongate footelement during the other of plantarflexion and dorsiflexion.

All of these embodiments are intended to be within the scope of thedisclosure herein. These and other embodiments will become readilyapparent to those skilled in the art from the following detaileddescription having reference to the attached figures, the disclosure notbeing limited to any particular disclosed embodiment(s).

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure are described with reference to the drawings of certainembodiments, which are intended to schematically illustrate certainembodiments and not to limit the disclosure.

FIG. 1A illustrates a front view of an example embodiment of aprosthetic foot having a mechanism for adjusting stiffness;

FIG. 1B illustrates a top view of the prosthetic foot of FIG. 1A;

FIG. 1C illustrates a rear view of the prosthetic foot of FIGS. 1A and1B;

FIGS. 2A-2D illustrate the prosthetic foot of FIGS. 1A-1C with themechanism for adjusting stiffness in various configurations;

FIG. 3 illustrates an example embodiment of a prosthetic foot having aspring mechanism for adjusting stiffness;

FIG. 4A illustrates the foot member and attachment adapter of theprosthetic foot of FIG. 3;

FIG. 4B illustrates a cross-sectional view of the spring mechanism ofFIG. 3 coupled to the foot member of FIG. 4A;

FIG. 4C illustrates the spring mechanism of FIGS. 3 and 4B;

FIG. 5 illustrates an example embodiment of a prosthetic foot having adual spring mechanism for adjusting stiffness;

FIG. 6A illustrates a cross-sectional view of the prosthetic foot ofFIG. 5;

FIG. 6B illustrates a cross-sectional view of the spring mechanismcoupled to the foot member of FIGS. 5 and 6A;

FIG. 6C illustrates a close-up view of the spring mechanism coupled tothe foot member of FIGS. 5-6B;

FIG. 7A illustrates a perspective view of an example embodiment of aprosthetic foot having an alternative dual spring mechanism foradjusting stiffness;

FIG. 7B illustrates a side view of the prosthetic foot of FIG. 7A;

FIG. 8A illustrates another example embodiment of a prosthetic footincluding the mechanism for adjusting stiffness of FIGS. 1A-3D;

FIG. 8B illustrates an exploded view of the prosthetic foot of FIG. 8A;

FIG. 9A illustrates an another example embodiment of a prosthetic footincluding the mechanism for adjusting stiffness of FIGS. 1A-3D;

FIG. 9B illustrates an exploded view of the prosthetic foot of FIG. 9A;

FIGS. 9C-9F illustrate an example embodiment of a foot element includinga drop-toe portion; and

FIGS. 10-13 illustrate various views of another example embodiment of aprosthetic foot having a mechanism for adjusting stiffness.

DETAILED DESCRIPTION

Although certain embodiments and examples are described below, those ofskill in the art will appreciate that the disclosure extends beyond thespecifically disclosed embodiments and/or uses and obvious modificationsand equivalents thereof. Thus, it is intended that the scope of thedisclosure herein disclosed should not be limited by any particularembodiments described below.

The present disclosure provides various examples of prosthetic feet andfeatures for prosthetic feet that advantageously allow for adjustment ofthe stiffness and/or flexibility of the feet. Prosthetic feet accordingto the present disclosure can include an elongate, plate-like footmember having a mechanism for variable or configurable stiffness in thefoot member. The prosthetic feet and features shown and described hereinadvantageously allow for customized independent control over theflexibility of the foot in either or both of dorsiflexion andplantarflexion.

FIGS. 1A-1C illustrate front, top, and rear view, respectively, of anexample embodiment of a prosthetic foot 100 including features thatallow for adjustable stiffness. The foot 100 includes an elongate footmember 110. In the illustrated embodiment, the foot member 110 is anupper foot member, and the foot 100 further includes a heel member 120.The illustrated foot member 110 is substantially J-shaped and extendsfrom a proximal end 112 located approximately at the location of theankle of a natural human foot downward and forward to a toe end 114. Adistal or forward end of the heel member 120 is coupled to the footmember 110 between the proximal end 112 and the toe end 114 with aportion of an upper surface of the heel member 120 facing and/orcontacting a portion of a lower surface of the foot member 110, and theheel member 120 extends rearwardly from the forward end to a heel end124. In the illustrated embodiment, the foot 100 further includes anattachment adapter 102 coupled to the proximal end 112 of the footmember 110. The attachment adapter 102 can include a connector, such aspyramid connector 104, for attaching the foot 100 to a user's residuallimb or another prosthetic component. Other configurations of attachmentadapters and/or connectors can also be used with the feet describedherein.

In some embodiments, the foot member 110 is constructed of a resilientmaterial capable of flexing in multiple directions. The foot member 110can include multiple layers or laminae. Examples of possible materialsfor the foot member 110 include carbon, any polymer material, and anycomposite of polymer and fiber. The polymer can be thermoset orthermoplastic. In a composite, the fiber reinforcement can be any typeof fiber, such as carbon, glass, or aramid. The fibers can be long andunidirectional, or they can be chopped and randomly oriented. In someembodiments, the heel member 120 is constructed similarly to the footmember 110.

In some embodiments, the foot member 110 includes a split 116 that atleast partially extends substantially along the longitudinal axis of thefoot member 110, as shown in FIGS. 1A and 1B. The heel member 120 canalso include a split 126 that at least partially extends substantiallyalong the longitudinal axis of the heel member 120, as shown in FIG. 1C.The splits 116, 126 allow medial and lateral portions of the foot member110 and heel member 120 to flex at least partially independently of eachother. The split 116 can begin in a rounded fillet, hole, or opening(for example, hole 118 shown in the embodiment of FIG. 8B). The hole 118can help prevent the formation of stress concentrations in that region.In other embodiments, the foot member 110 and/or heel member 120 do notinclude splits.

The foot member 110 includes a tongue portion 130 as shown in FIGS.1A-1C. The tongue portion 130 is defined or formed by a slot, groove, orslit 132 in the foot member 110 that extends through the entirethickness of the foot member 110 from a top or front surface 111 of thefoot member 110 to a bottom or back surface 113 of the foot member 110.Optionally, the slot 132 can be a generally U-shaped slot 132. Thetongue portion 130 extends longitudinally along a central axis of thefoot member 110. As shown, the base 134 or curved portion of the slot132 is positioned in a generally vertical portion of the foot member110, and the arms 136 a, 136 b or straight portions of the slot 132extend distally or forward toward the toe end 114. In the illustratedembodiment, the arms 136 a, 136 b extend parallel or generally parallelto one another and to a longitudinal axis of the foot member 110 alongat least a portion or a majority of their length. In some embodiments,the distal ends of the arms 136 a, 136 b include segments 137 a, 137 bthat extend outwardly (relative to the longitudinal axis of the footmember 110) at an angle relative to the remainder of the arms 136 a, 136b, for example as shown in FIGS. 1A and 1B. Advantageously, the tongueportion 130 can move relative to the rest of the foot member 110, andmovement of the tongue portion 130 relative to the rest of the footmember 110 can be selectively varied, as discussed further below, tovary the stiffness of the foot 100 during one or both of dorsiflexionand plantarflexion.

In some embodiments, the arms 136 a, 136 b and/or angled segments 137 a,137 b terminate in rounded fillets or openings 138 as illustrated. Theopenings 138 can advantageously help reduce or prevent the formation ofstress concentrations in that region. In some embodiments, the openings138 also or alternatively receive fasteners (e.g., bolts, screws, or thelike) that couple the heel member 120 to the foot member 110. In otherembodiments, the foot member 110 includes holes 139 configured toreceive fasteners that are separate from the openings 138 (for exampleas shown in FIG. 4A). In the embodiment illustrated in FIGS. 1A-1C, theslot 132 is symmetrical about the central longitudinal axis of the footmember 110 and the arms 136 a, 136 b have equal lengths. However, inother embodiments, the slot 132 may be asymmetrical. In someembodiments, a width of the tongue portion 130 can be about one-third toabout one-half of a width of the foot member 110. In other embodiments,the width of the tongue portion 130 can be less than a third or morethan a half of the width of the foot member 110.

In the illustrated embodiment, the foot member 110 is monolithic and thetongue portion 130 is integrally formed with the remainder of the footmember 110 and made of the same material as the rest of the foot member110. However, in other embodiments, the tongue portion 130 is made of adifferent material than the rest of the foot member 110. In some suchembodiments, the material for the tongue portion 130 can be incorporatedinto the molding process for the foot member 110 such that the footmember 110 is monolithic. Alternatively, the tongue portion 130 can beformed separately and coupled to the foot member 110. In someembodiments, the tongue portion can be made of a metal, polymer,plastic, or a fiber composition such as Spectra, Dacron, Kevlar, etc.

In use, the tongue portion 130 and portions of the foot member 110surrounding the tongue portion 130 can flex relative to each other. Thiscan increase the flexibility of the foot member 110. In someembodiments, the foot 100 includes a mechanism that allows the user or aprosthetist to adjust the direction and/or degree of stiffness and/orflexibility of the foot member 110.

In the embodiment illustrated in FIGS. 1A-1C, the foot 100 includes twoengagement members 140 a, 140 b coupled to or disposed adjacent thetongue portion 130. As shown, a first engagement member 140 a is coupledto or disposed on a front side 131 of the tongue portion 130, and asecond engagement member 140 b is coupled to or disposed on a back side133 of the tongue portion 130. In the illustrated embodiment, theengagement members 140 a, 140 b are semi-circular tabs and positionedwith the flat portion facing the foot member 110, although other shapesand configurations are also possible. In some embodiments, a postextends through the hole 118 and extends between and couples the frontengagement member 140 a and back engagement member 140 b. In embodimentsnot including a split, the post can extend through an aperture 160formed near the proximal end of the tongue portion 130, for example asshown in FIG. 4A. Although the illustrated embodiment includes a frontengagement member 140 a and a back engagement member 140 b, in otherembodiments, the foot 100 may include only a front engagement member 140a or only a back engagement member 140 b. The front engagement member140 a and back engagement member 140 b can be rotated relative to eachother and to the foot member 110 and can be positioned vertically, likethe front engagement member 140 a as shown in FIG. 1A, or horizontally,like the back engagement member 140 b as shown in FIG. 1C.

When the engagement members 140 a, 140 b are positioned vertically, theengagement members 140 a, 140 b do not extend beyond the width of thetongue portion 130. When the engagement members 140 a, 140 b arepositioned horizontally, the engagement members 140 a, 140 b extendacross the tongue portion 130, arms 136 a, 136 b of the slot 132, andportions of the foot member 110 adjacent the slot 132. The engagementmembers 140 a 140 b can be adjusted to adjust the flexibility and/orstiffness of the foot member 110. If both engagement members 140 a, 140b are positioned vertically as shown in FIG. 2A, the tongue portion 130is disconnected from the foot member 110 such that the tongue portion130 and the rest of the foot member 110 can flex at least somewhat orpartially independently of each other during use. This makes the footmember 110 more flexible when it moves in the plantarflexion anddorsiflexion direction because less of the foot member 110 is flexed(e.g., the tongue portion 130 does not contribute to the springresistance provided by the foot member 110 during flexion); that is, thetongue portion 130 is operably disconnected from the rest of the footmember 110. If both engagement members 140 a, 140 b are positionedhorizontally as shown in FIG. 2B, the tongue portion 130 is operablyconnected to the rest of the foot member 110 because contact between theouter edges or portions of the engagement members 140 a, 140 b andportions of the foot member 110 adjacent the slot 132 inhibits orprevents the tongue portion 130 from moving away from alignment with therest of the foot member. The tongue portion 130 therefore flexes withthe rest of the foot member 110, making the foot member 110 stiffer orless flexible when moved in plantarflexion and dorsiflexion.

If the front engagement member 140 a is positioned vertically and theback engagement member 140 b is positioned horizontally as shown in FIG.2C, the tongue member 130 is operably disconnected from the rest of thefoot member 110 during dorsiflexion, but operably connected to the restof the foot member 110 during plantarflexion. As the foot beginsplantarflexing upon heel strike, the toe end 114 begins moving forwardand away from the proximal end 112 coupled to the user's residual limbor another prosthetic component. As the tongue portion attempts to moveforward with the toe end 114, the outer portions of the horizontal backengagement member 140 b contact the portions of the foot member 110adjacent the slot 132 and prevent or inhibit the tongue portion 130 frommoving forward away from the rest of the foot member 110. Therefore, thestiffness of the foot member 110 during plantarflexion is provided bythe resistance to flexion of the tongue member 130 in combination withthat of the rest of the foot member 110. As the foot dorsiflexes whenapproaching toe off, the proximal end 112 of the foot member movesforward and toward the toe end 114 of the foot member 110 in contactwith the ground. The vertical front engagement member 140 a does notcontact the rest of the foot member 110 and allows the rest of the footmember 110 to move forward without the tongue portion 130. That is, asthe foot member 110 dorsiflexes, the tongue member 130 is operablydisconnected from the rest of the foot member 110 and does not flex, sothat the tongue member 130 does not contribute to the stiffness orresistance to flexion of the rest of the foot member 110 duringdorsiflexion. This arrangement makes the foot member 110 relativelystiffer during heel strike and/or plantarflexion following heel strike(in other words, the foot 100 has a stiff heel) and relatively moreflexible during dorsiflexion approaching and/or during toe off (the foot100 has a soft toe).

Conversely, if the front engagement member 140 a is positionedhorizontally and the back engagement member 140 b is positionedvertically as shown in FIG. 2D, the tongue member 130 is operablyconnected to the rest of the foot member 110 during dorsiflexion andoperably disconnected from the rest of the foot member 110 duringplantarflexion. This arrangement therefore makes the foot member 110relatively more flexible during heel strike and/or plantarflexionfollowing heel strike (the foot has a soft heel) and relatively stifferduring dorsiflexion, such as during toe off (the foot 100 has a stifftoe). Such a configuration can advantageously provide both a dampeningfunction (i.e., if the tongue portion 130 is allowed to flex at leastsomewhat independently of the rest of the foot member 110 at heelstrike) and an energy return function (i.e., if the tongue portion 130is operably connected to the rest of the foot member 110 when the footmember 110 is fully dorsiflexed just prior to initiating toe off).

The front 140 a and rear 140 b engagement members allow the user or aprosthetist to adjust the foot member 110 to be either relatively stiffor relatively flexible during dorsiflexion and/or plantarflexion. Thetongue portion 130 can be either operably connected or disconnected fromthe rest of the foot member 110 in dorsiflexion and operably connectedor disconnected from the rest of the foot member 110 in plantarflexion.In other embodiments, the foot member 110 includes an adjustmentmechanism that allows for adjustment of the degree to which the tongueportion 130 is engaged with or operably connected to the foot member110. Such a mechanism provides for greater variability in the range ofstiffness and/or flexibility to which the foot member 110 can beadjusted.

For example, FIGS. 3-4C illustrate an example embodiment of a footmember 110 including a spring adjustment mechanism 150. As shown in FIG.4C, the spring adjustment mechanism 150 includes shaft 154, a flange 152a at a first end of the shaft 154, an adjustment knob 158 at a secondend of the shaft 154, a washer 152 b slidably positioned on the shaft154 between the first flange 152 a and adjustment knob 158 (in otherwords, the washer 152 b can translate along the shaft 154, and a spring156 extending between and coupled to the washer 152 b and adjustmentknob 158). The shaft 154 of the spring adjustment mechanism 150 extendsthrough the aperture 160 of the tongue portion, the flange 152 a isdisposed adjacent or positioned against the front side 111 of the footmember 110 and front side 131 of the tongue portion 130, and the washer152 b is disposed on the back side 113 of the foot member 110 and backside 133 of the tongue portion 130, as shown in FIG. 4B. In someembodiments in which the foot member 110 includes a split 132 beginningin a hole 118, for example as shown in FIG. 9, the shaft 154 extendsthrough the hole 118.

In the illustrated embodiment, the flange 152 a contacts portions of thefoot member 110 adjacent the slot 132 when the foot dorsiflexes suchthat the tongue 130 is operably connected to the rest of the foot member110 in dorsiflexion. In some embodiments, the spring 156 biases thewasher 152 b against the back of the foot member 110. Because the washer152 b can slide along the shaft 154 as the spring compresses andrelaxes, the tongue portion 130 can move independently of the rest ofthe foot member 110 to some extent when the foot plantarflexes. Theadjustment knob 158 can be rotated in a first direction to compress thespring 156 and the opposite direction to relax the spring 156 (e.g., togradually vary a stiffness of the foot member 110). As the degree oramount of compression of the spring 156 increases (e.g., due to rotationof the knob 158), the range of motion of the washer 152 b along theshaft 154 decreases, and the tongue portion 130 becomes more operablyconnected to the rest of the foot member 110, making the foot member 110stiffer or less flexible in plantarflexion.

Although in the illustrated embodiment the spring 156 and adjustmentknob 158 are positioned on the back of the foot member 110, in otherembodiments, the orientation of the spring adjustment mechanism 150 canbe reversed such that the spring 156 and adjustment knob 158 arepositioned on the front of the foot member 110. In such an embodiment,the flange 152 a contacts portions of the foot member 110 adjacent theslot 132 when the foot plantarflexes such that the tongue portion 130 isoperably connected to the rest of the foot member 110 in plantarflexion,but the washer 152 b can slide along the shaft 154 during dorsiflexionso that the tongue portion 130 can be operably disconnected from therest of the foot member 110 during at least a portion of dorsiflexion.

FIGS. 5-6C illustrate another embodiment of a spring adjustmentmechanism 170 including two springs. In the illustrated embodiment, theadjustment mechanism 170 includes a shaft 174, an adjustment knob 178coupled to one end of the shaft 174 and disposed behind the foot member110, a flange 172 a coupled to the other end of the shaft 174 anddisposed in front of the foot member 110, a front washer 172 b slidablydisposed on the shaft 174 in front of the foot member 110, a back washer172 c slidably disposed on the shaft 174 behind the foot member 110, afront spring 176 b extending between and coupled to the flange 172 a andthe front washer 172 b, and a back spring 176 a extending between andcoupled to the back washer 172 c and the adjustment knob 178. In otherembodiments, the adjustment mechanism 170 can be reversed such that theflange 172 a is positioned behind the foot member 110 and the adjustmentknob 178 is positioned in front of the foot member 110. The two springconfiguration can advantageously allow the adjustment mechanism 170 andtherefore the stiffness of the foot member 110 to be tuned with moresensitivity compared to a one-spring adjustment mechanism. The twoslidable washers 172 b, 172 c in the two spring configuration allow thetongue portion 130 to be operably disconnected from and move relative tothe rest of the foot member 110 during at least a portion of bothdorsiflexion and plantarflexion.

Spring adjustment mechanisms such as mechanisms 150, 170 shown in FIGS.3-6C advantageously allow the flexibility of the foot member 110 to beadjusted or tuned with greater variability compared to the adjustmentmechanism shown in FIGS. 1A-2D and described herein (that is, with aspring mechanism the flexibility can be adjusted over a range of degreesof flexibility or stiffness, whereas the adjustment mechanism of FIGS.1A-2D generally allows for selection between two degrees of flexibilityin dorsiflexion and two degrees of flexibility in plantarflexion).However, with the spring adjustment mechanism 170 having a singleadjustment knob 178, the stiffness or flexibility of the foot member 110in both dorsiflexion and plantarflexion are controlled or adjustedtogether, whereas the adjustment mechanism of FIGS. 1A-2D allows thestiffness or flexibility in dorsiflexion to be adjusted independently ofthat in plantarflexion.

FIGS. 7A and 7B illustrate an alternative spring adjustment mechanism180 including front 186 b and back 186 a springs as well as front 188 band back 188 a adjustment knobs. This configuration advantageouslyallows for independent control and adjustment of each spring andtherefore independent control and adjustment of the flexibility of thefoot member 110 during dorsiflexion and plantarflexion. The front spring186 b and front adjustment knob 188 b control or adjust the stiffness orflexibility of the foot member 110 in dorsiflexion, and the back spring186 a and back adjustment knob 188 a control or adjust the stiffness orflexibility of the foot member 110 in plantarflexion.

Although mechanical engagement member and spring type adjustmentmechanisms have been shown and described herein, other adjustmentmechanisms are also possible to control movement of the tongue portion130 relative to the remainder of the foot member 110. For example, thespring mechanism 150, 170 can be replaced with hydraulic, pneumatic, ormotorized adjustment mechanisms. The spring mechanisms 150, 170 can alsobe replaced with other mechanical adjustment mechanisms, for example,including components or inserts made of rubber, elastic, polymers, orother materials.

The adjustment mechanisms shown and described herein, and otheradjustment mechanisms according to the present disclosure, can also beincorporated into prosthetic feet having other configurations. Forexample, FIGS. 8A-8B illustrate another example embodiment of aprosthetic foot 200 incorporating foot member 110 and front 140 a andback 140 b engagement members. In the illustrated embodiment, theprosthetic foot 200 also includes a heel member 120, an upper footmember 210, and an adapter 202 including a pyramid connector 104.However, in other embodiments, the foot 200 does not include the upperfoot member 210. In this embodiment, the foot member 110 is generallyC-shaped such that the foot member 110 extends from a generallyhorizontal proximal end 112 to a generally horizontal toe end 114 andincludes a generally forwardly-facing concave curved portion between theproximal end 112 and the toe end 114. The upper foot member 210 isdisposed generally above the foot member 110 and is also generallyC-shaped. The upper foot member 210 extends from a generally horizontalproximal end 212 to a toe end 214. In the illustrated embodiment, theupper foot member 210 is shorter than the foot member 110 such that thetoe end 214 of the upper foot member 210 is proximal to the toe end 114of the foot member 110. The upper foot member 210 can include a split216 extending along at least a portion of a longitudinal axis of theupper foot member 210. The proximal ends 112, 212 of the foot member 110and upper foot member 212 are received in a rearwardly facing cavity ofthe adapter 202. In some embodiments, the proximal ends 112, 212 of thefoot member 110 and upper foot member 212 can be secured to the adapter202 and/or each other with a curable material, for example, epoxy. Theadapter 202 can include one or more inlet holes 204 that are in fluidcommunication with the rearwardly facing cavity of the adapter 202 sothat the inlet holes 204 can serve as injection points for theintroduction of the curable material to the cavity. Additional detailson features of prosthetic feet and adapters having configurationssimilar to prosthetic foot 200 and adapter 202 can be found in U.S.Publication No. 2013/0144403, entitled “Prosthetic Foot with Dual FootBlades and Vertically Offset Toe,” the entirety of which is herebyincorporated by reference herein and should be considered a part of thisspecification.

In the illustrated embodiment, a crepe portion 115 is attached to theunderside of the toe end 114 of the foot member 110. As shown, the crepeportion 115 can be aligned with the toe end 114 of the foot member 110so as to not extend past the toe end 114. Preferably, the crepe portion115 comprises a resilient pad or cushion. For example, the crepe portion115 can be made of a compressible material. The crepe portion 115 canalso be made of a porous material. In some embodiments, the crepeportion 115 can be made of solid urethane. In one preferred embodiment,the crepe portion 115 is attached to the toe end 114 of the foot member110 with an adhesive. However, other attachment means can be used, suchas bolts, screws, and bands wrapped around the crepe portion 115 and thefoot member 110. The crepe portion 115 is preferably configured to havea shape corresponding to the shape of the foot member 110. For example,the crepe portion 115 can have a rounded edge corresponding to therounded distal edge of the toe end 114. In the illustrated embodiment,the crepe portion 115 has a uniform thickness. In another preferredembodiment, the crepe portion 115 can have a varying thickness. Forexample, the crepe portion 115 can have a decreasing thickness in thedirection of the distal end of the foot member 110. In other preferredembodiments, the foot member 110 does not have a crepe portion 115attached to it, so that the toe end 114 of the foot member 110operatively contacts the support surface.

In the embodiment shown in FIGS. 8A-8B, the upper foot member 210, footmember 110, and heel member 120 are coupled via fasteners 128 (e.g.,bolts, screws, or the like) that extend through the openings 138 in thefoot member 110, corresponding openings 238 near the toe end 214 of theupper foot member 210, and corresponding openings near the forward endof the heel member 120. In the illustrated embodiment, the prostheticfoot 200 includes a resilient member 121, such as a wedge, disposedbetween the heel member 120 and the foot member 110. The resilientmember 121 can separate at least a portion of the foot member 110 fromthe heel member 120. In some embodiments, the resilient member cancompletely separate the foot member 110 from the heel member 120. Theresilient member 121 can be removably disposed between the heel member120 and foot member 110 or fixed between the heel member 120 and footmember 110, e.g., with an adhesive, bolts, or screw. The resilientmember 121 can provide shock absorption to the prosthetic foot 200. Insome embodiments, the resilient member 121 can be made, for example, ofa hard plastic, such as polyurethane or polypropylene. The resilientmember 121 can also be made of a more compressible material, such asfoam, natural or synthetic rubbers, or the like. However, the resilientmember 121 can be made of any material that provides adequate shockabsorption. In some embodiments, a spacer 123 is disposed between aportion the foot member 110 and the upper foot member 210 proximate thetoe end 214 of the upper foot member 210. In some embodiments, thespacer 123 creates a gap between the foot member 110 and the upper footmember 210. The spacer can advantageously provide noise reduction duringoperation of the prosthetic foot 200, for example, to reduce noise dueto friction between the foot member 110 and upper foot member 210 whenthe members 110, 210 contact each other. In the illustrated embodiment,the spacer 123 has a longitudinal split 125 that is aligned with thesplits 116, 216, 126 in the foot member 110, upper foot member 210, andheel member 120, respectively.

As shown, the upper foot member 210 includes an opening 230 extendingalong a portion of the upper foot member 210. In the illustratedembodiment, the split 216 extends from the opening 230 to the toe end214, although in other embodiments, the split 216 may not extend to theopening 230 or to the toe end 214. The opening 230 is wide enough toaccommodate the front engagement member 140 a when turned horizontally,as shown in FIG. 8A. In the illustrated embodiment, the foot member 110includes an aperture extension 135 extending upwardly or proximally fromthe base 134 of the slot 132. The aperture extension 135 can be sized toaccommodate the front engagement member 140 a when turned vertically.

In some alternative embodiments, the prosthetic foot 200 includes aspring adjustment mechanism as described herein. In other embodimentsincluding either the mechanical engagement member adjustment mechanismor a spring adjustment mechanism, the foot member 110 may have a lowprofile shape in which the toe end is generally horizontally orientedand a proximal section is inclined at an angle relative to the toe endand relative to a support surface. The foot member 110 can also beincorporated into various other configurations of prosthetic feet.

FIGS. 9A-9B illustrate another example embodiment of a prosthetic foot200′. Prosthetic foot 200′ is similar to prosthetic foot 200. However,in prosthetic foot 200′, the foot member 110 is approximately the samelength as, or does not extend significantly distal to the toe end 214of, the upper foot member 210. Instead of heel member 120, prostheticfoot 200′ includes a lower foot member 250 that extends from a heel end252 to a toe end 254. Additional details on features of lower footmembers and prosthetic feet having configurations similar to prostheticfoot 200′ can be found in U.S. application Ser. No. 14/755,464, entitled“Prosthetic Feet and Foot covers,” the entirety of which is herebyincorporated by reference herein and should be considered a part of thisspecification.

In some embodiments, a forefoot region 253 of the lower foot member 250is wider than an arch region 255 and/or a heel region 251 of the footmember 250. The forefoot region 253 can be wider than a forefoot regionof previously available prosthetic feet. For example, in some previouslyavailable prosthetic feet, the ratio of the width of the forefoot regionto the length of the foot element is about 25-26%. In some prostheticfeet according to the present disclosure, the ratio of the width of theforefoot region 253 to the length of the foot element is about 30%.

In some embodiments, a toe region 257 of the lower foot member 250includes a generally U-shaped cut-out portion, slot or gap 256 extendinginwardly from the toe end 254. In some embodiments, the cut-out 256 ispositioned toward a medial side of a longitudinal axis of the lower footmember 250, but is spaced from a medial edge of the lower foot member250 (e.g., the cut-out portion or gap 256 is defined between thelongitudinal axis and medial edge of the lower foot member 250). Thecut-out 256 gives the lower foot member 250 a “sandal toe” appearanceand/or function and defines a structural “big toe” 259. The cut outportion 256 can receive a strap of a sandal. Because the forefoot region253 is wider than a remainder of the foot element and wider thanpreviously available prosthetic feet, the cut-out 256 and big toe 259can be offset from the longitudinal axis of the lower foot member 250 toa greater extent. In the illustrated embodiment, the big toe 259 islonger (e.g., extends further distally) than the remaining “toes” or theremainder of the toe portion 257. This can advantageously provide thelower foot member 250 with a full length toe lever and allow the lowerfoot member 250 to more closely approximate or mimic a natural humanfoot during rollover. The cut-out portion 256 can provide the toe region257 of the lower foot member 250 with a lesser stiffness on the medialside, which can help guide the center of mass of the foot 200′ towardthe medial side during rollover.

In some embodiments, the lower foot member 250 includes a split 258 thatat least partially separates the lower foot member 250 into a medialportion and a lateral portion. In the illustrated embodiment, the split258 does not extend to the heel end 252 of the lower foot member 250. Inthe illustrated embodiment, the slit 258 extends substantially straightfrom a proximal end (or end of the split 258 closest to the heel end252) through the arch region 255, then curves medially in the forefootregion 253 or approximately at a border between the arch region 255 andthe forefoot region 253 and extends to the cut out 256. However, otherconfigurations for the split 258 are also possible. For example, inother embodiments, the split 258 can be entirely straight, can beentirely curved, and/or can extend to a medial or lateral edge of thelower foot member 250.

FIGS. 9C-9F illustrate an example embodiment of a lower foot member 250that includes a drop-toe or vertically offset toe portion. In theillustrated embodiment, a forefoot piece 260 is coupled, eitherpermanently or removably, to a bottom surface of at least a portion ofthe forefoot region 253 and/or toe region 257 of the lower foot member250. In some embodiments, the forefoot piece 260 is made of a hardplastic, such as polyurethane or polypropylene. The forefoot piece 260can also be made of a more compressible material, such as foam, naturalor synthetic rubbers, or the like. Other materials are also possible. Asshown in the illustrated embodiment, the bottom surface of the forefootregion 253 and toe region 257 can be flattened or straight (rather thancurved) to accommodate a forefoot piece 260 having a flat or straightupper surface. In other embodiments, the bottom surface of the forefootregion 253 and toe region 257 can be curved or partially curved toaccommodate a forefoot piece 260 having a curved or partially curvedupper surface. As shown, the forefoot piece 260 is generally sized andshaped to correspond to the forefoot region 253 and/or toe region 257 ofthe lower foot member 250, and a distal end of the forefoot piece 260can include a cut-out 266 that corresponds in shape and size to thecut-out 256 of the lower foot member 250.

In the illustrated embodiment, a bottom surface of the forefoot piece260 is curved or downward-facing convex. In some embodiments, the bottomsurface of the forefoot piece 260 has a curvature that is discontinuousrelative to and/or different from the curvature of the lower surface ofthe lower foot member 250 proximal to the forefoot piece 260. The bottomsurface of the forefoot piece 260 may therefore be downwardly verticallyoffset from a remainder of the lower foot member 250 proximal to theforefoot piece 260. The forefoot piece 260 can advantageously allow forthe lower foot member 250 to be supported during stance at portions ofthe heel and toe regions rather than at the heel and fasteners 128 thatcouple other foot elements, such as foot member 110 and upper footmember 210, to the lower foot member 250. This allows for enhancedsuspension and increased vertical displacement of the lower foot member250 during stance because the fasteners are not in contact with theground.

FIGS. 10-13 illustrate an example embodiment of a prosthetic foot 300including another mechanism for adjusting stiffness and/or flexibility.The foot 300 includes a lower foot member 320, an upper foot member 310,an attachment adapter 330 having a pyramid connector 104, and a C-member340. In the illustrated embodiment, the lower foot member 320 extendsfrom a heel end 322 to a toe end 324, and the upper foot member 310 hasa substantially C-shape extending from a proximal end 312 coupled to theattachment adapter 330 to a distal end 314 that is coupled to the lowerfoot member 320 proximal to or rearward of the toe end 324. In theillustrated embodiment, the upper foot member 310 includes a split 317extending through a portion of the upper foot member 310. In otherembodiments, the upper foot member 310 can extend to a toe end, and thefoot 300 can include a heel member, for example, similar to heel member120, rather than the lower foot member 320.

The C-member 340 is positioned generally in front of the upper footmember 310, and the curvature of the C-member 340 generally correspondsto that of the upper foot member 310. In the illustrated embodiment, aspacer 360 is positioned between a distal or lower end 343 of theC-member 340 and the upper foot member 310. As shown, the foot 300 caninclude a second spacer 362 disposed on the opposite (back) side of thefoot member 310 from the first spacer 360. The C-member 340 includes anaperture 344 at or near the distal end 343 and a slot 346 near an upperor proximal end 342 as shown in FIGS. 10-11 and 13. The upper footmember 310 includes a slot 316 as shown in FIG. 12. In the illustratedembodiment, the split 317 extends from the slot 316 to the distal end314 of the upper foot member 310. A lower surface of the attachmentadapter 330 includes an aperture 332 as shown in FIG. 12.

In some embodiments, C-member 340 can be releasably coupled to the upperfoot member 310 via a fastener that extends through the aperture 344 ofthe C-member 340, an aperture 364 in the first spacer 360, the slot 316of the upper foot member 310, and an aperture in the second spacer 362.In the illustrated embodiment, the C-member 340 is also releasablycoupled to the attachment adapter 330 via an adjustment assembly 348.The adjustment assembly 348 includes a body portion 354 and a handle 350pivotally or hingedly coupled to the body portion 354 at pivot 352. Thebody portion 354 includes a post that extends through the slot 346 ofthe C-member 340 and into the aperture 332 of the attachment adapter330. When the handle 350 is positioned extending laterally as shown inFIG. 10, the body portion 354 applies pressure to the C-member 340 tolock the C-member 340 against the attachment adapter 330.

During ambulation, the gap between the upper foot member 310 andC-member 340 closes as the foot moves from heel strike to toe off. Asthe gap closes, the prosthetic foot 300 becomes stiffer. To alter thestiffness characteristics of the foot 300, the position of the C-member340 relative to the upper foot member 310 can be adjusted. To do so, theuser or a prosthetist can release the fastener extending through theaperture 344, first spacer 360, upper foot member 310, and second spacer362 and pivot the handle 350 of the adjustment assembly 348 away fromthe upper foot member 310 to unlock the C-member 340 from the attachmentadapter 330. The user or prosthetist can then slide the C-member 340along the upper foot member 310 so that the fastener extending throughthe aperture 344, first spacer 360, upper foot member 310, and secondspacer 362 travels in the slot 316, and the first 360 and second 362spacers slide or move relative to the upper foot member 310 along withthe distal end 343 of the C-member 340. Simultaneously, the post of thebody portion 354 of the adjustment assembly 348 remains stationary, butthe slot 346 allows the C-member 340 to move relative to the post. Whenthe user or prosthetist has adjusted the C-member 340 to the desiredposition, he or she can resecure the fastener extending through theaperture 344, first spacer 360, upper foot member 310, and second spacer362 and pivot the handle 350 of the adjustment assembly 348 back towardthe upper foot member 310 to lock the C-member 340 to the attachmentadapter 330.

Although this disclosure has been described in the context of certainembodiments and examples, it will be understood by those skilled in theart that the disclosure extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses and obviousmodifications and equivalents thereof. In addition, while severalvariations of the embodiments of the disclosure have been shown anddescribed in detail, other modifications, which are within the scope ofthis disclosure, will be readily apparent to those of skill in the art.It is also contemplated that various combinations or sub-combinations ofthe specific features and aspects of the embodiments may be made andstill fall within the scope of the disclosure. For example, featuresdescribed above in connection with one embodiment can be used with adifferent embodiment described herein and the combination still fallwithin the scope of the disclosure. It should be understood that variousfeatures and aspects of the disclosed embodiments can be combined with,or substituted for, one another in order to form varying modes of theembodiments of the disclosure. Thus, it is intended that the scope ofthe disclosure herein should not be limited by the particularembodiments described above. Accordingly, unless otherwise stated, orunless clearly incompatible, each embodiment of this invention maycomprise, additional to its essential features described herein, one ormore features as described herein from each other embodiment of theinvention disclosed herein.

Features, materials, characteristics, or groups described in conjunctionwith a particular aspect, embodiment, or example are to be understood tobe applicable to any other aspect, embodiment or example described inthis section or elsewhere in this specification unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The protection is notrestricted to the details of any foregoing embodiments. The protectionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

Furthermore, certain features that are described in this disclosure inthe context of separate implementations can also be implemented incombination in a single implementation. Conversely, various featuresthat are described in the context of a single implementation can also beimplemented in multiple implementations separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations, one or more features from a claimedcombination can, in some cases, be excised from the combination, and thecombination may be claimed as a subcombination or variation of asubcombination.

Moreover, while operations may be depicted in the drawings or describedin the specification in a particular order, such operations need not beperformed in the particular order shown or in sequential order, or thatall operations be performed, to achieve desirable results. Otheroperations that are not depicted or described can be incorporated in theexample methods and processes. For example, one or more additionaloperations can be performed before, after, simultaneously, or betweenany of the described operations. Further, the operations may berearranged or reordered in other implementations. Those skilled in theart will appreciate that in some embodiments, the actual steps taken inthe processes illustrated and/or disclosed may differ from those shownin the figures. Depending on the embodiment, certain of the stepsdescribed above may be removed, others may be added. Furthermore, thefeatures and attributes of the specific embodiments disclosed above maybe combined in different ways to form additional embodiments, all ofwhich fall within the scope of the present disclosure. Also, theseparation of various system components in the implementations describedabove should not be understood as requiring such separation in allimplementations, and it should be understood that the describedcomponents and systems can generally be integrated together in a singleproduct or packaged into multiple products.

For purposes of this disclosure, certain aspects, advantages, and novelfeatures are described herein. Not necessarily all such advantages maybe achieved in accordance with any particular embodiment. Thus, forexample, those skilled in the art will recognize that the disclosure maybe embodied or carried out in a manner that achieves one advantage or agroup of advantages as taught herein without necessarily achieving otheradvantages as may be taught or suggested herein.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements, and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements, and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements, and/or steps areincluded or are to be performed in any particular embodiment.

Conjunctive language such as the phrase “at least one of X, Y, and Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to convey that an item, term, etc. may beeither X, Y, or Z. Thus, such conjunctive language is not generallyintended to imply that certain embodiments require the presence of atleast one of X, at least one of Y, and at least one of Z.

Language of degree used herein, such as the terms “approximately,”“about,” “generally,” and “substantially” as used herein represent avalue, amount, or characteristic close to the stated value, amount, orcharacteristic that still performs a desired function or achieves adesired result. For example, the terms “approximately”, “about”,“generally,” and “substantially” may refer to an amount that is withinless than 10% of, within less than 5% of, within less than 1% of, withinless than 0.1% of, and within less than 0.01% of the stated amount. Asanother example, in certain embodiments, the terms “generally parallel”and “substantially parallel” refer to a value, amount, or characteristicthat departs from exactly parallel by less than or equal to 15 degrees,10 degrees, 5 degrees, 3 degrees, 1 degree, 0.1 degree, or otherwise.

The scope of the present disclosure is not intended to be limited by thespecific disclosures of preferred embodiments in this section orelsewhere in this specification, and may be defined by claims aspresented in this section or elsewhere in this specification or aspresented in the future. The language of the claims is to be interpretedbroadly based on the language employed in the claims and not limited tothe examples described in the present specification or during theprosecution of the application, which examples are to be construed asnon-exclusive.

What is claimed is:
 1. A prosthetic foot comprising: an elongate footelement extending from a proximal end to a distal end, the foot elementcomprising a tongue portion defined by a slot in the foot element thatat least partially separates the tongue portion from a remainder of theelongate foot element; and a mechanism comprising at least one tabengagement member, wherein the tongue portion is operatively connectedto the remainder of the elongate foot element when the tab engagementmember is positioned in a first orientation and the tongue portion isoperatively disconnected from the remainder of the elongate foot elementwhen the tab engagement member is positioned in a second orientation,and wherein the at least one tab engagement member extends beyond awidth of the tongue portion when in the first orientation and does notextend beyond the width of the tongue portion when in the secondorientation, and wherein, when the tongue portion is operativelyconnected to the remainder of the elongate foot element, the elongatefoot element exhibits relatively greater stiffness, and when the tongueportion is operatively disconnected from the remainder of the elongatefoot element, the elongate foot element exhibits relatively lowerstiffness.
 2. The prosthetic foot of claim 1, wherein the mechanism isconfigured to be selectively actuated to adjust the stiffness of thefoot element in one or both of plantarflexion and dorsiflexion.
 3. Theprosthetic foot of claim 1, wherein the at least one tab engagementmember comprises two tab engagement members, a first tab engagementmember disposed on a front side of the elongate foot element and asecond tab engagement member disposed on a back side of the elongatefoot element.
 4. The prosthetic foot of claim 3, wherein the first andsecond tab engagement members are coupled by a post extending betweenthe first and second tab engagement members.
 5. The prosthetic foot ofclaim 1, wherein when the tongue portion is operatively connected to theremainder of the elongate foot element the tongue portion flexes withthe remainder of the elongate foot element, and when the tongue portionis operatively disconnected from the remainder of the elongate footelement the tongue portion flexes at least partially independently ofthe remainder of the elongate foot element.
 6. The prosthetic foot ofclaim 1, further comprising a second foot element disposed below thefoot element, wherein the second foot element is coupled to the footelement by fasteners extending through openings in the foot element andthe second foot element.
 7. The prosthetic foot of claim 6, furthercomprising a third foot element disposed above the elongate footelement, the third foot element comprising an opening extending along aportion of the third foot element, wherein the opening has a width toaccommodate the tab engagement member in the first orientation.
 8. Theprosthetic foot of claim 1, further comprising an adapter coupled to thefoot element proximate to the proximal end.
 9. The prosthetic foot ofclaim 1, wherein a distal end of the slot is proximal to the distal endof the elongate foot element and a distal end of the tongue portion isfixed relative to the remainder of the elongate foot element.
 10. Theprosthetic foot of claim 9, wherein the slot is U-shaped.
 11. Theprosthetic foot of claim 1, wherein the elongate foot element isgenerally C-shaped.
 12. A prosthetic foot comprising: a first elongatefoot element extending from a proximal end to a distal end, the footelement comprising a tongue portion defined by a slot in the footelement that at least partially separates the tongue portion from aremainder of the elongate foot element; a second foot element extendingfrom a heel end to an anterior end, the second foot element disposedbelow and coupled to the first elongate foot element, wherein the distalend of the first elongate foot element is positioned proximal of theanterior end of the second foot element, the anterior end of the secondelongate foot member defining a toe end of the prosthetic foot; and amechanism comprising at least one tab engagement member, wherein thetongue portion is operatively connected to the remainder of the firstelongate foot element when the tab engagement member is positioned in afirst orientation and the tongue portion is operatively disconnectedfrom the remainder of the first elongate foot element when the tabengagement member is positioned in a second orientation, wherein, whenthe tongue portion is operatively connected to the remainder of thefirst elongate foot element, the first elongate foot element exhibitsrelatively greater stiffness, and when the tongue portion is operativelydisconnected from the remainder of the first elongate foot element, thefirst elongate foot element exhibits relatively lower stiffness.
 13. Theprosthetic foot of claim 12, wherein the at least one tab engagementmember comprises two tab engagement members, a first tab engagementmember disposed on a front side of the first elongate foot element and asecond tab engagement member disposed on a back side of the firstelongate foot element.
 14. The prosthetic foot of claim 13, wherein thefirst and second tab engagement members are coupled by a post extendingbetween the first and second tab engagement members, the first andsecond tab engagement members being rotatable independent of each otherabout an axis of the post.
 15. The prosthetic foot of claim 12, whereinthe at least one tab engagement member extends beyond a width of thetongue portion when in the first orientation and does not extend beyondthe width of the tongue portion when in the second orientation.
 16. Theprosthetic foot of claim 12, wherein the first elongate foot element isgenerally C-shaped.
 17. The prosthetic foot of claim 12, wherein whenthe tongue portion is operatively connected to the remainder of thefirst elongate foot element the tongue portion flexes with the remainderof the first elongate foot element, and when the tongue portion isoperatively disconnected from the remainder of the first elongate footelement the tongue portion flexes at least partially independently ofthe remainder of the first elongate foot element.
 18. The prostheticfoot of claim 12, wherein a distal end of the slot is proximal to thedistal end of the first elongate foot element and a distal end of thetongue portion is fixed relative to the remainder of the first elongatefoot element.
 19. The prosthetic foot of claim 18, wherein the slot isU-shaped.
 20. The prosthetic foot of claim 12, further comprising anadapter coupled to the first foot element proximate to the proximal end.21. The prosthetic foot of claim 12, further comprising a third footelement disposed above the first foot element, the third foot elementcomprising an opening extending along a portion of the third footelement, wherein the opening has a width to accommodate the tabengagement member in the first orientation.